textproduct: Rapid City

KEY MESSAGES

- Light precipitation possible through tonight.

- Moderate to heavy snowfall expected for much of the area Saturday into Sunday.

- Warm and mostly dry conditions return for next week.

DISCUSSION

(This Evening Through Friday) Issued at 117 PM MDT Fri Mar 13 2026

Northwest upper flow continues over the forecast area today, as mild troughing sits over the Great Lakes region. Surface analysis shows warm frontal boundary running from northeastern WY down into southwestern SD this afternoon. North of the warm front, radar shows light precipitation ongoing from northwest down into south central SD. Winds are relatively light this afternoon with temperatures in the 30s to upper 40s.

Mid-level forcing will continue to bring areas of light precipitation over the region through tonight. Best chance for light accumulations are expected over northwestern SD. Upper trough thats currently sitting over the PAC NW coast will traverse southeast the rest of today, moving into the northern plains on Saturday. Strong forcing associated with this wave will bring moderate to heavy precipitation into the forecast area starting late Saturday morning in northwestern SD and over spreading the region throughout the day. Baroclinic zone is expected over the FA, and will result in some areas in the southern half of the area seeing rain to start or a rain/snow mix, before transitioning. Associated cold front with this system will move south throughout the day, bringing arctic air behind it. Frontogenesis banding is expected Saturday evening into Sunday morning. Currently models differ a bit on where the heavier banding will set up, but overall consensus points to northwestern into northern SD, where 4-8 inches of snowfall will be possible between Saturday afternoon and Sunday morning. Have issued a Winter Storm Warning covering northwestern SD as well as the northern and Wyoming Black Hills where upslope enhancement is expected to bring 6-10 inches in the higher elevation areas. Further south, a bit lighter snowfall accumulations are expected closer to I-90, however strong winds will accompany the snowfall behind the front. Have issued a Winter Storm Advisory for areas along I-90 east of the Black hills into south central SD, as well as parts of the northeastern WY plains counties. These areas can expect generally 2-5 inches of snow, but stronger wind gusts up to 40-50 mph behind the cold front. Precipitation will taper off from west to east Sunday morning into the afternoon, however gusty winds may linger a bit into the early evening hours.

Looking ahead into next week, following this winter system upper ridging builds over the western CONUS Sunday night and sticks around for much of next week. This will result in mostly dry conditions and a warming trend. Highs by Tuesday bounce back into the mid 50s and 60s, and longer range models point to potential for record breaking highs later in the work week. Thursday and Friday look to be the warmest days, where highs could even reach into the 80s for some areas.

AVIATION

(For the 00Z TAFS Through 00Z Saturday Evening) Issued At 426 PM MDT Fri Mar 13 2026

MVFR/IFR conditions in low stratus/patchy light snow will persist across portions of western SD plains and far northeastern WY this evening into the overnight hours. Meanwhile, smoke will bring KCUT down to IFR visbilities at times. VFR conditions expected across southwestern into south central SD.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Winter Storm Warning from noon Saturday to noon MDT Sunday for SDZ001-002-014-078. Winter Storm Warning from 3 PM Saturday to noon MDT Sunday for SDZ012-013-024-025-032-072-073. Winter Weather Advisory from 6 PM MDT /7 PM CDT/ Saturday to noon MDT /1 PM CDT/ Sunday for SDZ026-031-042>044-046-047- 049-076-077. WY...Winter Storm Warning from 3 PM Saturday to noon MDT Sunday for WYZ057-060. Winter Weather Advisory from 6 PM Saturday to noon MDT Sunday for WYZ054>056.